fimBmpIo.cpp

//
// Copyright (c) Singular Inversions Inc. 2010
//
// Authors:     Andrew Beatty
// Created:     July 7, 2010
//
 
#include "stdafx.h"
 
#include "fimBmpIo.hpp"
#include "FgSerial.hpp"
#include "fimImgOps.hpp"
#include "FgFile.hpp"
 
using namespace std;
 
namespace Fg {
 
struct  DibHeader
{
  uint32    header_sz;
  uint32    width;
  uint32    height;
  uint16    nplanes;
  uint16    bitspp;
  uint32    compress_type;
  uint32    bmp_bytesz;
  uint32    hres;
  uint32    vres;
  uint32    ncolors;
  uint32    nimpcolors;
};
 
bool
fg3ReadBmpSimple(
    String8 const &    fname,
    FimImgRgbaUbC &     img)
{
    Ifstream      ifs(fname,false);
    if (!ifs)
        return false;
    string          magic = "  ";
    ifs.read(&magic[0],2);
    if (magic != "BM")
        fgThrow("File is not a BMP file",fname);
    uint32          bmpSize,
                    dummy,
                    offset;
    ifs.read((char*)&bmpSize,4);
    ifs.read((char*)&dummy,4);
    ifs.read((char*)&offset,4);
    DibHeader       header;
    ifs.read((char*)&header,sizeof(header));
    if ((header.header_sz != 40) ||
        (header.nplanes != 1) ||
        (!((header.bitspp == 32) || (header.bitspp == 24) || (header.bitspp == 8))) ||
        (header.compress_type != 0))
        fgThrow("Unsupported DIB type",fname);
    img.resize(header.width,header.height);
    uint            skip = offset-54;
    for (uint ii=0; ii<skip; ++ii)
        ifs.read((char*)&dummy,1);
    uint            nr = img.height() - 1;
    for (uint row=0; row<img.height(); ++row)
    {
        for (uint col=0; col<img.width(); ++col)
        {
            ifs.read((char*)&(img[nr-row][col].c[2]),1);
            if (header.bitspp == 32)
            {
                ifs.read((char*)&(img[nr-row][col].c[1]),1);
                ifs.read((char*)&(img[nr-row][col].c[0]),1);
                ifs.read((char*)&(img[nr-row][col].c[3]),1);
            }
            else if (header.bitspp == 24)
            {
                ifs.read((char*)&(img[nr-row][col].c[1]),1);
                ifs.read((char*)&(img[nr-row][col].c[0]),1);
                img[nr-row][col].c[3] = 255;
            }
            else
            {
                img[nr-row][col].c[1] = img[nr-row][col].c[2];
                img[nr-row][col].c[0] = img[nr-row][col].c[2];
                img[nr-row][col].c[3] = 255;
            }
        }
    }
    return true;
}
 
bool
fg3ReadBmpSimple(
    String8 const &    fname,
    FimImgUbC &         img)
{
    FimImgRgbaUbC   tmp;
    if (!fg3ReadBmpSimple(fname,tmp))
        return false;
    img.resize(tmp.width(),tmp.height());
    for (uint row=0; row<img.height(); ++row)
        for (uint col=0; col<img.width(); ++col)
            img[row][col] = tmp[row][col].c[0];
    return true;
}
 
bool
fg3WriteBmp(
    String8 const &        fname,
    const FimImgRgbaUbC &   img)
{
    Ofstream      ofs(fname,false);
    if (!ofs)
        return false;
    ofs.write("BM",2);
    uint32          bmpSize = 3 * img.width() * img.height() + 54,
                    dummy = 0,
                    offset = 54;
    ofs.write((char*)&bmpSize,4);
    ofs.write((char*)&dummy,4);
    ofs.write((char*)&offset,4);
    DibHeader       header;
    header.header_sz = 40;
    header.width = img.width();
    header.height = img.height();
    header.nplanes = 1;
    header.bitspp = 24;
    header.compress_type = 0;
    header.bmp_bytesz = 3 * img.width() * img.height();
    header.hres = 0;
    header.vres = 0;
    header.ncolors = 0;
    header.nimpcolors = 0;
    ofs.write((char*)&header,40);
    uint            nr = img.height() - 1;
    for (uint row=0; row<img.height(); ++row)
    {
        for (uint col=0; col<img.width(); ++col)
        {
            ofs.write((char*)&(img[nr-row][col].c[2]),1);
            ofs.write((char*)&(img[nr-row][col].c[1]),1);
            ofs.write((char*)&(img[nr-row][col].c[0]),1);
        }
    }
    return true;
}
 
}